Cant press spells

So I was in ARAM but this has happened in summoners rift before where when I pressed a spell it wouldn't work it would end up with me pinging a warning instead of pressing my abilities. So like if I tired to press my ult on Eve it wouldn't happen and then i try to click the screen when i did it showed i was sending a warning ping. I'm not sure if that made any sense but this bug ruined my game and we lost the game because of it. Any thoughts?